The inventions combines the fields of high voltage transmission towers and pultruded composite construction. The inventor has several patents and several pending applications that relate in one way or another to interlocking joints formed of pultruded composites. A pultruded composite is a mass of fibers, generally fiberglass, that are pulled through the die rather than being pushed (extruded). Currently, virtually all such towers are made of steel. However, there are inherent limitations of steel towers primarily because of the conductive nature of steel. This requires that enormous towers must be used both to separate the individual conductors from the steel structure and to accommodate inter-tower sag.
There are few large structures made of pultruded composites. This is partly due to the fact that when composite members are fastened with conventional fasteners such as bolts and screws, the joint strength suffers unacceptably.
However, nuts and bolts are not the only ways to hold composite members together. The inventor has developed a number of interlocking joint structures that do not require passing a hole through the members.